Among the existing air-conditioning systems, there is an air-conditioning system which includes a plurality of air-conditioning devices and a relay device which relays communications between the air-conditioning devices for which communication protocols are different from each other (e.g., see Patent Literature 1).
In addition, among the existing air-conditioning systems, there is an air-conditioning system which includes a plurality of air-conditioning devices for each of which a control program is updated (e.g., see Patent Literature 2).